Which of the following movement is not related to auxin level

Options

A. Bending of shoot towards light
B. Movement of root towards soil
C. Nyctinastic leaf movements
D. Movement of sunflower head tracking the sun

Explanation

To determine which movement is not related to auxin levels, we can analyze the options provided in the question. Here’s a step-by-step solution:

### Step 1: Understand Auxin's Role
Auxin is a plant hormone that regulates various growth processes, including cell elongation, phototropism (growth towards light), and geotropism (growth in response to gravity).

**Hint:** Remember that auxin is primarily involved in directional growth responses in plants.

### Step 2: Identify the Movements Related to Auxin
1. **Phototropism**: This is the bending of the shoot towards light, which is influenced by auxin levels causing differential growth on the sides of the plant.
2. **Geotropism**: This refers to the movement of roots towards the soil, also regulated by auxin.
3. **Sunflower Head Movement**: The tracking of the sunflower head towards the sun is another form of phototropism, influenced by auxin.

**Hint:** Look for movements that involve growth direction towards stimuli, as these are typically regulated by auxin.

### Step 3: Identify the Movement Not Related to Auxin
The fourth option mentioned is **Nyctinasty**. This is the movement of plants in response to the onset of darkness or light, such as the opening and closing of flowers. Nyctinastic movements are not primarily influenced by auxin but are more related to circadian rhythms and other factors.

**Hint:** Consider movements that are not directly related to growth direction or hormone levels.

### Step 4: Conclusion
Based on the analysis, the movement that is not related to auxin levels is **Nyctinasty**.

**Final Answer:** Nyctinasty is the movement not related to auxin levels.